The runner-up for the Democratic presidential nomination is pledging to be a more unifying force at that party’s convention next week than the runner-up for the Republican nomination has been this week.

A spokesman for Bernie Sanders said Thursday that when the liberal senator from Vermont addresses the Democratic convention, he plans to echo many of the themes he touched upon last week during a rally in New Hampshire at which he formally endorsed Hillary Clinton.

“He’s not Ted Cruz, in so many ways,” said Sanders spokesman Michael Briggs, referring to the conservative Republican senator from Texas whose address Wednesday night is now the talk of the GOP convention.

Cruz drew hearty boos from the convention floor during a speech in which he declined to endorse Republican nominee Donald Trump. During a breakfast Thursday morning with the Texas delegation in Cleveland, Cruz delivered a lengthy defense of his exhortation to Republicans the night before to “vote your conscience.”

Before the Democratic convention in Philadelphia officially gets underway on Monday, Sanders plans to address a gathering of many of the more than 1,900 delegates representing him. Briggs said the talk will be an opportunity for them “to hear what he thinks he’s accomplished in the past year and where we go from here.”

Whether Sanders’s delegates will be as committed to party unity remains an open question.

An independent group billing itself as the Bernie Delegates Network has raised the specter of a protest on the convention floor if Clinton picks Sen. Timothy M. Kaine (Va.) or “a similar VP choice” as her running mate.

“If she chooses someone like herself … there’s going to be blowback,” said Jeff Cohen, an organizer for the network, which both he and Briggs said is not working under the direction of Sanders.

Cohen said said many Sanders’s delegates would prefer a more progressive choice, such as Sen. Elizabeth Warren (D-Mass.), about whom Sanders has also spoken favorably.

“It’s my view that if Clinton chose Warren, it would be a much less contentious convention,” Cohen said.

Many Sanders delegates also have problems with the potential pick of Tom Vilsack, the U.S. agriculture secretary and former Iowa governor, Cohen said, because they consider him too close to “corporate agri-business.”

Cohen said that more than 1,200 Sanders delegates have signed up on the group’s web site, which serves as a way to keep in touch with one another. In a recent survey, he said, about 200 indicated they would be prepared to take part in a protest on the convention floor if Clinton chose a “corporate-oriented running mate deemed unacceptable.”